Conventionally, pigments whose surfaces are coated with various types of compounds have been used as pigments to be contained in makeup products such as foundations, eyeshadow and blushers or basic skin care such as sunscreen products, emulsions and creams with a view to improve waterproofness and avoid coming off of makeup or to improve feeling of the pigments and so forth.
Here, coating pigment surfaces with a silicone compound or a fluorine compound has been known as a means of improving the waterproofness (see Patent Documents 1 and 2). Cosmetic pigments whose surfaces are coated with the silicone compound or fluorine compound excel in avoiding coming off of makeup and contribute to long-lasting makeup because waterproofness is imparted to them. However, there are some problems that they give a dried out and less moist feeling owing to the compounds, and skin adhesion becomes poor because they have less affinity to a biological body.
Meanwhile, coating pigment surfaces with collagen has been known as a means of improving feeling of the pigments (see Patent Document 3). However, since the collagen is an animal protein, there is a limit in the use of it, which is a problem.
Recently, due to the increasing popularity of natural products among consumers, cosmetics using compounds derived from natural products are greatly desired, and development of cosmetics which are human-body friendly having good skin adhesion and which provide good feeling are strongly desired.
Surfactants (biosurfactants) such as glucolipids are said to have great biodegradability and low toxicity and they are environmentally-friendly. Therefore, applying them to a food industry, cosmetic industry, drug industry, chemical industry, environmental field etc. has been considered. However, existing biosurfactants have poor hydrophobicity, so that they are not suitable for cosmetic pigments. Meanwhile, although mannosylerythritol lipid (MEL) has been known, for use in skin care, as having curative properties against skin roughness because it can easily form a lamellar structure, there has been no report that it is used as cosmetic pigments.